Thermostatic vent valve

ABSTRACT

A temperature responsive vent valve for use in air supported structures is disclosed. The valve utilizes a flexible flap connected to the interior surface of the air dome, the position of which is varied by a bimetallic strip connected thereto. In the closed position of the flexible flap, it seals off adjacent air openings in the air dome cover. When higher temperatures change the curvature of the bimetallic strip, the flexible flap is drawn away from the openings to allow an outflow of air to thus compensate for an expansion within the structure due to increased temperature and to reduce the interior temperature within the structure.

United States Patent [19] Benjamin [4 Nov. 11, 1975 1 1 THERMOSTATIC VENT VALVE [75] Inventor: Gary L. Benjamin, Mount [52] US. Cl 52/1; 52/2; 236/101 E; 236/93 [51] Int. Cl. E04B U345 [58] Field of Search 236/101 E, 93 R, 49; 52/1, 52/2; 251/75; 137/79 3,799,432 3/1974 Schneider 236/101 E 3,810,262 5/1974 Strand 52/2 FOREIGN PATENTS OR APPLICATIONS 209,039 10/1959 Austria 239/93 798,350 7/1958 United Kingdom 236/93 Primary Examiner-Frank L. Abbott Assistant E.\'aminerI-I. E. Raduazo Attorney, Agent, or Firm-Thomas M. Freiburger; Vincent L. Barker, Jr.

[57] ABSTRACT A temperature responsive vent valve for use in air supported structures is disclosed. The valve utilizes a flexible flap connected to the interior surface of the air dome, the position of which is varied by a bimetallic strip connected thereto. In the closed position of the flexible flap, it seals off adjacent air openings in the air dome cover. When higher temperatures change the curvature of the bimetallic strip, the flexible flap is drawn away from the openings to allow an outflow of air to thus compensate for an expansion within the structure due to increased temperature and to reduce the interior temperature within the structure.

3 Claims, 6 Drawing Figures THERMOSTATIC VENT VALVE BACKGROUND OF THE INVENTION The invention relates to air supported structures, and more particularly to a novel temperature responsive valve for use in such structures for regulating the temperature and pressure within the enclosure by varying the amount of air allowed to escape therefrom.

Air supported structures of the type to which this invention relates are shown in US. Pat. Nos. 3,304,664, 3,110,519, 3,769,763 and 3,810,262. The structures are employed to enclose such areas as swimming pools, tennis courts, gardens and other areas which need warmth and protection during seasons of marginal weather. US. Pat. Nos. 3,304,664 and 3,810,262 show pressure relieving and regulating means in connection with such air domes. Various ventilators utilizing bimetallic strips to regulate openings are shown in US. Pat. Nos. 1,757,987, 3,027,090 and 3,368,756.

In air supported structures, a blower situated outside the structure generally directs outside air into the structure to keep it inflated, by raising the pressure inside the structure slightly above atmospheric. Means .are often provided for limiting or regulating the pressure inside the air dome by shutting off the air blower in response to the attainment of a certain pressure or by relieving excess air pressure through a relief valve in the walls of the structure. In some air domes, air pressure is limited simply by using a blower of low enough power output that it will not further compress air over a certain pressure limit.

None of these pressure-limiting means provides effective temperature regulation. With direct sunlight on an air supported structure at outside temperatures above about 65F, a high heat load is usually developed inside the inflated structure, making conditions very uncomfortable for those inside the structure. A means is therefore necessary in connection with such structures for limiting the inside air temperature.

SUMMARY OF THE INVENTION The present invention provides a simple and effective temperature responsive ventilating valve for air supported structures. Located preferably on the ceiling of the inflatable structure, the ventilating valve includes a flexible flap secured to the structures inner surface from approximately its middle. Holes through the structure adjacent the location of the flap cooperate with the flap to provide closure and air flow regulation. When the holes are opened by retraction of the flap, warm air in the upper part of the structure is exhausted and replaced by cooler outside air admitted by the air blower. Positioning of the flap is controlled by a bimetallic strip which stretches in an are from one end of the flap to the other. The bimetallic strip is slightly arced with its convex surface downward and its more thermally expansive metal also downward, so that increases in temperature within the air dome tend to sharpen the arc and move the flexible flap inward away from the vent holes. Location of the valving device on a ceiling portion of the structure takes advantage of gravity to aid in the inward movement of the flap when the arc of the bimetallic strip increases due to interior temperature rise.

When the temperature within the air dome decreases to a low enough point, the bimetallic strip straightens to such an extent that it draws the flexible flap taut,

causing it to rise up against the air openings in the structure. The slightly above atmospheric air pressure within the structure completes the sea] by pushing the flap tightly against the air openings. The seals are tight enough to prevent rain from entering the air dome.

The air outflow openings in the inflatable structure are provided with a plurality of individual caps so that maximum air outflow can be regulated. In addition, the sizing of the outflow openings and the positioning and configuration of the flap and bimetallic strip are coordinated with the size of the air blower feeding the structure such that at the maximum open position of the air openings, the air blower remains adequate to sustain inflation of the structure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional elevational view showing an air supported structure employing a thermostatic vent valve according to the invention, with the valve being exaggerated in size;

FIG. 2 is an enlarged sectional elevational view indicating the manner of operation of the ventilating valve;

FIG. 3 is an inverted plan view showing the ventilating valve as it appears from the inside of the structure;

FIG. 4 is a sectional view taken along the line 44 of FIG. 2;

FIG. 5 is a sectional view taken along the line 55 of FIG. 3; and

FIG. 6 is a sectional view similar to FIG. 5 showing a modified form of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, an air supported structure or air dome 10 is shown enclosing a swimming pool 11. Air is pumped into the enclosure 10 at pressure slightly above atmospheric by an air-blower 12 connected to the enclosure 10 by a duct 13. To maintain the structure 10 in position, water tubes 14 extend around the periphery of the structure 10 and act as an anchor. A thermostatic vent valve 16 according to the invention is shown in the ceiling of the air supported structure 10.

The vent valve assembly 16 is shown in greater detail in FIGS. 2, 3, 4 and 5. A portion 17 of the ceiling of the air dome 10 is provided with a plurality of openings 18 and 19 therein directly above an elongate oval shaped flexible flap 21. The flap 21 is fastened to the ceiling portion 17 along a transverse central seam 22 which may be formed by adhesive sealing, heat sealing, ultrasonic bonding or other fastening means. The flap 21 is preferably formed from a vinyl material reinforced with nylon fibers, so that the flap has strength as well as flexibility. However, any other suitable flexible material may be used to form the flap 21.

Connected to the ends of the flap 21 and depending interiorly therefrom is a bimetallic strip 23 which has its more thermally expansive metal 24 on its downward, convex surface and is less thermally expansive metal 26 upward, as seen in FIGS. 2, 4 and 5. When the temperature inside the air dome l0 rises, the lower metal strip 24 expands to a greater extent than the upper metal strip 26, causing the bimetallic strip 23 to form into a more sharply bowed configuration. This brings more closely together the hooked ends 27 and 28 of the bimetallic strip, which are connected by brackets 29 and 30 to the ends of the flap 21. When the ends of the bimetallic strip 23 are thus drawn together, they relax the tension exerted upon the flap 21, allowing the flap to sag downwardly as shown in broken line in FIG. 2. The higher the inside temperature of the air dome 10, the lower the flap 21 sags, and the less restricted the air openings 18 and 19 become. Of course, at very high temperatures a maximum air flow condition is established by the sagging of the flap 21 to the extent that little or no further increase in air flow occurs due to additional increases in the sharpness of the curvature of the bimetallic strip 23. As discussed above, the air blower 12 is sized to be adequate for keeping the air dome inflated under this condition.

FIG. 6 shows another means for connection of a bimetallic strip to the flexible flap 21. A control member 31 connected to the brackets 29 and 30 and effective to regulate the flap 21 includes a bimetallic strip 35 and a connecting strut 37 firmly attached to each end. The vertical portion of the strut 37 increases the effect that changes in curvature in the bimetallic strip have on the position of the flexible flap 21. I.e., the longer the vertical leg of the strut 37, the closer together the ends of the flap 21 will be moved for a given curvature of the strip 35.

As the ceiling openings 18 and 19 in the air dome 10 are opened in response to higher interior temperatures, air is circulated at a more rapid rate through the air dome 10 with fresh outside air being delivered by the air blower 12 and the hottest air within the structure being exhausted through the ceiling openings. During the season of use of the air dome 10 over a swimming pool, for example, the apparatus 16 is thus able to maintain a constant comfortable temperature range within the structure.

The invention also includes apparatus for adjusting the range of temperature maintained within the structure 10. Caps 32 and 33 connected to the ceiling portion 17 by flexible stems 34 are provided for covering the air openings 18 and 19. The caps 32 and 33 may be of the type described in U.S. Pat. No. 2,777,920. In the closed position, the caps 32 and 33 tightly engage flexible annular flanges 36 around the openings 18 and 19, sealing the openings 18 and 19 and tightly retaining the caps in place. The purpose of the caps 32 and 33 is to regulate the amount of air outflow from the air dome 10 for given positions of the flap 21. As seen in FIG. 3, the preferred embodiment has six such air holes 18, 19 and caps 32 and 33. Certain of the caps 32 and 33 may be closed in order to reduce the air outflow, thereby increasing the temperature within the structure 10. This would be desirable when rather high temperatures are to be maintained within the structure 10 or simply to maintain normal temperatures on a cool but sunny day. On such days, smaller amounts of outside air are needed to cool the interior of the air dome 10. The caps 32 and 33 may be opened or closed while the dome 10 is deflated or by utilizing a tool (not shown) for handling the caps from the exterior during full inflation. When utilized over a swimming pool, the dome 10 can be deflated with its caps 32 and 33 closed to become a pool cover.

The particular structure of the thermostatic vent valve 16 and use of the arcuate bimetallic strip 23 results in effective temperature controlling ventilation without undue influence of variations in the strength of the suns radiation upon the structure 10. The bimetallic strip 23 is positioned to depend downwardly specifically for this purpose. Its positioning enables it to respond to inside air temperature rather than to the temperature of the air dome ceiling itself; it is shielded from direct solar radiation by the flap 21. If the arcuate bimetallic strip 23 were reversed and connected by its midpoint to the air dome ceiling, with a flap attached to the upper side thereof for engaging the air openings, such an apparatus would be functional but would respond to the temperature of the air dome surface to such an extent that effective temperature regulation within the structure 10 could not be maintained. On a cool day with warm sun, the structure 10 would be warmed to a rather high temperature, and the adjacent bimetallic strip would be similarly warmed so that the air openings would remain open. This would keep cool air flowing at a relatively high volume rate through the air dome 10, keeping temperatures too low. On a warmer day with the sun not so bright, however, the bimetallic strip would be more responsive to interior temperature of the air dome l0. Constant adjustment of the caps 32 and 33 would therefore be necessary in response to changes in the surface temperature of the structure 10 because of variation in the suns radiation.

Although the vent valve 16 of the invention is preferably located in a ceiling surface of the air dome 10, it may also be positioned elsewhere, such as in an inclined side surface of the structure. In such position, biasing means may be required to initiate the opening of the flap 21 when the bimetallic strip 23 initially bends to bring its ends closer together, since gravity will not have as great an opening influence in this location. Such means could comprise the pre-shaping of the flap 21 into an arcuate configuration, for example, so that when in the closed position it would have a slight tendency to open.

The above described preferred embodiment provides a thermostatic vent valve which is simple and economical to manufacture and which results in effective temperature regulation within an air supported structure. Various other embodiments and alterations to this preferred embodiment will be apparent to those skilled in the art and may be made without departing from the spirit and scope of the following claims.

I claim:

1. In an air supported structure having side and ceiling surfaces and connected to a source of pressurized air, a temperature responsive ventilating valve comprising a flap of flexible material connected from its approximate center to the interior ceiling of the structure, at least one vent opening in the ceiling of the structure adjacent the upper surface of said flexible flap, and a bimetallic strip below said flexible flap with its ends operably connected to the ends of said flap, said bimetallic strip defining an arcuate configuration with its concave surface disposed upwardly and its more thermally expansive surface disposed downwardly.

2. The apparatus of claim 1 wherein said vent openings include means for varying the size thereof.

3. The apparatus of claim 2 wherein said means comprises a cap disposed to fit over and close at least one of said vent openings.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, Dated November 111 1975 Inventor(s) Gag L. Benjamin It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line ll,' "3,110,519" should be -3,7lO,5l9-.

Signed and Scaled this second Day Of March 1976 v [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer I Commissioner nj'latenls and Trademarks 

1. In an air supported structure having side and ceiling surfaces and connected to a source of pressurized air, a temperature responsive ventilating valve comprising a flap of flexible material connected from its approximate center to the interior ceiling of the structure, at least one vent opening in the ceiling of the structure adjacent the upper surface of said flexible flap, and a bimetallic strip below said flexible flap with its ends operably connected to the ends of said flap, said bimetallic strip defining an arcuate configuration with its concave surface disposed upwardly and its more thermally expansive surface disposed downwardly.
 2. The apparatus of claim 1 wherein said vent openings include means for varying the size thereof.
 3. The apparatus of claim 2 wherein said means comprises a cap disposed to fit over and close at least one of said vent openings. 